How do I get the emissons light off (not a problem with the lambda sensor)?

Question

When I bought the car the light was on but the previous owner showed documentation that the car had been tested for this twice by VW themselves; they had changed the lambda sensor but she said it had come back on the next day (don't know why she put up with this). Anyway, I was quite assured that it wasn't an engine maintenance issue after seeing the test certificate from VW.
I recently took the car for it's first service since I've had it and mentioned this to the mechanic. When I went back to collect it he tells me that he'd managed to get the light off by changing the lambda sensor (which isn't cheap). I re-explained things to him and came close to falling out with him (someone I've known for several years) and in the end came to an agreement.
Nonetheless, even though he kept the car for another few days to try other things, he couldn't get the light to stay off and why the light is still on is a mystery.
Has anyone else had this problem and/or suggestions as to how to turn off?

Answer 1

Hi



I'm going to assume that this is either a no activity or a low output from the lambda sensor, and that the injector pulse is slightly high.



The Lambda sensor is trying to turn up the fuelling due to a fault elsewhere causing a lean condition.



The checks to be made are:-



1) Air leaks

2) Coolant sensor

3) Airflow sensor

4) Fuel pressure regulator

5) Fuel pressure

6) A clogged injector(s)

7) Throttle position sensor/switch



A lot of people make the mistake of blaming the O2 (lambda) sensor when it becomes over or under active, when in fact it is actually attempting to correct the fuel trim.



Cheers



Geordie

Answer 2

the emmisions light on volkswagens come o nfor more than just the lambda probe.

the main two things to set off the emmisions are

A)as suggested the lambda probe or

B) the coolant emp sensor,

i work as a vw qualified technician so regularly diagnos these faults with our vags 5051 machine and many customers are amazed that the coolant temp sensor brings o nthe emmisions light, but it does, so get that checked too.

note- vw use o2 sensors/lambda sensors and NOX sensors. these are all sensors in the exhaust that measure emmisions.

Answer 3

you have not mentioned which vw you bought. most vw's apart from old small engined models have 2 lambda sensors, have both been changed or 1 twice?. the vehicle will need to be reset on vehicle management system after replacement to reset memory.

Answer 4

It's clearly something other than the lamda sensor and the only way is to get the codes read off, I'm afraid.

It's an engine management warning light, not just an emissions warning light, and you could have a problem with any of several sensors.

Answer 5

ring up and join vw assistance it costs about £140 then wait 24 hours then call them to look at your car they will only join you up if car less than 10 yrs old their technicians are second to none, its better than going to the dealerships i worked on vw assistance till last year i hope this helps

Answer 6

you need to get a dremill os something similar and drill a small hole through the bulb or take the bulb out if you can get to it the first option is easier